This invention relates to spiral tube winding methods and apparatus, and more particularly to such methods and apparatus in which the presence or absence of various possible plies being wound to form the tube is sensed to at least partly control the operation of the tube winder.
Spiral tube winders which wind one or more longitudinal strips or plies of paper, plastic, foil, etc., on a mandrel to form a continuously advancing tube are well known as shown, for example, by Meyer U.S. Pat. No. 4,473,368. Such machines typically include a glue roller or other means for applying glue to at least one of the plies going to the mandrel. If any ply to which glue is being applied breaks between the glue application point and the mandrel, that ply may become fouled in the glue applying apparatus. This can damage the glue application apparatus and/or can make resuming normal operation a considerable chore (e.g. by necessitating partial disassembly and/or extensive cleaning of the glue application apparatus).
It is therefore an object of this invention to improve spiral tube winding methods and apparatus.
It is a more particular object of this invention to provide spiral tube winders which stop automatically whenever one of the plies being glued breaks.
In addition to the foregoing, spiral tube winders are sometimes constructed to wind various numbers of plies. If ply break sensing is provided, it must be possible to activate it for only those ply lanes which are currently in use. If such activation must be performed by the human operator of the apparatus, the operator may sometimes forget that a ply has been added and fail to activate the ply break detector for the lane handling that ply. If that ply breaks, the machine will not stop as the operator expects, and all of the foregoing problems may result even though the machine is equipped with a ply break sensor system.
It is therefore another object of this invention to provide a ply break sensor system which automatically detects which ply lanes are in use so that a break in the ply in any of those lanes can be detected in order to stop the machine.